The cooling system is the heart of any car, but for a crossover Nissan Murano the second generation with the Z51 body index, it plays a critical role. Equipped with a powerful V6 engine, this vehicle generates a significant amount of heat that must be efficiently dissipated. If you are the owner of this model, then you know that overheating can lead to catastrophic consequences, including deformation of the cylinder head.
Cooling radiator on Nissan Murano Z51 is a complex engineering product consisting of aluminum plates and plastic tanks. Over time, due to corrosion, mechanical damage or manufacturing defects, heat transfer efficiency decreases. In this article, we will look at how to recognize a malfunction, which radiator to choose for replacement, and how to carry out the work yourself without extra costs.
Design and features of the Murano Z51 cooling system
Cooling system Nissan Murano The Z51 is designed to withstand high powertrain loads. The radiator here is not just a metal grille, but a complex assembly that includes the main heat exchange unit, an expansion tank and a built-in heat exchanger for the automatic transmission. It is the presence of a built-in automatic transmission radiator that distinguishes this design from simple models where these systems are separated.
Materials used in production original radiator, include aluminum for the core and heat-resistant plastic for the side tanks. This combination provides light weight and high corrosion resistance. However, plastic loses its properties over time under the influence of high temperatures and vibrations, which often causes leaks.
It is important to understand that Nissan Murano Z51s often install additional radiators for the air conditioning and intercooler (if there is a turbocharged version, although this is rare for the Z51, more often it is just a condenser). All of them are located in a dense “bouquet” in front of the main radiator, which makes access difficult and increases the risk of damage from flying stones.
The main signs of a radiator malfunction
How to understand that something is wrong with the radiator? The most obvious signal is the overheating light on the dashboard coming on. But waiting for this moment is dangerous. Noticeable leaks of coolant on the asphalt under the hood or a characteristic sweetish smell of antifreeze in the cabin are sure signs that the tightness of the system is broken.
Sometimes the problem manifests itself not in loss of fluid, but in overheating in traffic jams. If the temperature gauge rises above normal at low speeds, but cools down on the highway, the circulation may be impaired or the radiator honeycombs may be clogged. Also pay attention to the color of the antifreeze: if it has become rusty or oil stains are visible in it, this may indicate destruction of the plastic tanks or a breakdown of the automatic transmission heat exchanger gasket.
Don't ignore strange sounds. A hissing or gurgling noise under the hood after stopping the engine may indicate air entering the system due to a crack in the housing radiator. Early diagnosis will save you thousands of rubles on engine repairs.
⚠️ Attention: If you notice an oily emulsion on the expansion tank cap, stop using the vehicle immediately. This is a sign that oil from the automatic transmission has entered the cooling system through a damaged heat exchanger inside the radiator.
Choosing a radiator: original or high-quality analogue?
In the spare parts market for Nissan Murano The Z51 comes in a variety of variants. The original (OEM) guarantees a perfect match in size and throughput, but its price can be significantly higher than average. Original radiator part numbers change frequently, so you should check your vehicle's VIN before purchasing.
Analogues offer a more affordable price, but the quality varies greatly. Famous brands such as Nissens, Denso or Behr-Hella, produce radiators that often even surpass the original in cooling efficiency. However, cheap Chinese copies may have thin honeycombs that break from the first hit with a stone, and low-quality plastic that cracks after just a year.
When choosing, pay attention to the number of rows of tubes and the thickness of the core. For Nissan Murano With the VQ35DE engine, it is critical to maintain factory heat dissipation parameters. A low-quality radiator may not be able to cope with the load in hot weather, which will lead to constant overheating and failure of the cylinder head gasket.
- ✅ Check the presence of a built-in heat exchanger for automatic transmission in the selected model.
- ✅ Compare the overall dimensions with your old radiator, even if the article number is the same.
- ✅ Give preference to brands with European or Japanese assembly for reliability.
- Original radiator
- High-quality analogue (Denso/Nissens)
- Budget analogue
- I buy second-hand from disassembly
Step-by-step instructions for replacing the radiator
Replacing the radiator with Nissan Murano Z51 is a task of medium complexity that requires accuracy and special tools. You will need a set of wrenches, a container to drain the antifreeze, new clamps, and possibly new coolant. The process begins by draining the old fluid, but this must be done on a cold engine to avoid burns.
The first step is to remove the engine protection and the lower air intake deflector. Then disconnect the pipes going to the radiator. Be prepared for residual antifreeze to leak out of them. Disconnect the electrical connectors for the fans and temperature sensors. Sometimes you have to remove the front bumper for easy access, although on some versions this can be done without it.
After dismantling the old unit, thoroughly clean the installation site from dirt and remnants of old rubber. Installing a new radiator requires the reverse sequence. Pay special attention to tightening the clamps: they must be securely fixed, but not overtightened, so as not to push through the plastic of the tank. Use only new clamps, as old ones may not provide a tight seal.
☑️ Preparing to replace the radiator
⚠️ Attention: When working with the cooling system, be sure to use gloves and safety glasses. Antifreeze is toxic and its vapors are harmful if inhaled.
Flushing and servicing the cooling system
If the radiator has no mechanical damage, but cooling efficiency is reduced, it may be clogged from the inside or outside. External cleanliness is achieved with a pressurized water jet, but be careful not to bend the thin aluminum plates. Internal flushing requires the use of special chemicals that remove scale and corrosive deposits.
For high-quality flushing of the system on Nissan Murano Z51 it is better to use distilled water and special cleaners. Regular tap water can leave new deposits. The flushing process includes adding chemicals, warming up the engine to operating temperature and subsequent long-term draining with rinsing with clean water until the effluent is clear.
Don't forget about the expansion tank. Sediment often accumulates in it, which clogs the thin radiator channels. It is recommended to dismantle the tank and wash it separately. Also check the condition of the radiator cap: the valve in it should work properly, creating the necessary excess pressure to increase the boiling point of the liquid.
Why can't you use regular water for rinsing?
Ordinary water contains calcium and magnesium salts, which precipitate when heated, forming scale. This reduces heat transfer and may cause the engine to overheat in the future.
When replacing the radiator, always change the antifreeze as well. The old fluid loses its anti-corrosion properties and can accelerate the destruction of the new radiator from the inside.
Specifications and Compatibility
When ordering parts, it is important to know the exact configuration of your vehicle. Nissan Murano The Z51 was equipped with various modifications of engines and gearboxes, which influenced the design of the radiator. The main parameters that you need to focus on include the number of tubes in the core and the type of connection of the automatic transmission pipes.
Below is a table with the main characteristics for the most common modifications:
| Engine modification | Volume (l) | Radiator type | Availability of automatic transmission heat exchanger | Original article (example) |
|---|---|---|---|---|
| VQ35DE | 3.5 | Aluminium/Plastic | Yes | 21460-ZW00A |
| VQ35DE (RWD) | 3.5 | Aluminium/Plastic | Yes | 21460-ZW01A |
| VQ35DE (AWD) | 3.5 | Reinforced | Yes | 21460-ZW02A |
| SL/Platinum package | 3.5 | With additional cooler | Yes | 21460-ZW03A |
Please note that even slight differences in pipe geometry may make installation impossible. If you buy a radiator from disassembly, be sure to check the integrity of the plastic tanks and the absence of cracks in the soldering areas. Hidden defects may appear immediately after starting the engine.
Frequent errors during replacement and maintenance
Many owners Nissan Murano They make the mistake of skimping on clamps or antifreeze. Cheap clamps weaken over time or cut through the plastic, leading to sudden leaks at the worst possible time. It is also not recommended to mix antifreeze of different colors and manufacturers, as a chemical reaction can lead to the formation of a gel that clogs the radiator.
Another common problem is improper removal of air from the system. If the bleeding procedure is not performed properly, air pockets will form in the system. This will lead to local overheating of the engine, even if the fluid level in the reservoir is normal. The pumping process requires repeated warming up of the engine and opening a special tap (if provided for by the design).
Ignoring the condition of the fans can also be fatal. Even a new radiator will not work efficiently if one of the electric fans does not turn on or is spinning in the wrong direction. Before installing a new radiator, check the operation of all components of the cooling system.
⚠️ Attention: After replacing the radiator, be sure to perform a pressure leak test. Use a special pressure tester to make sure there are no micro-leaks before starting active use.
A high-quality radiator is the key to a long engine life. Saving on this part often leads to an expensive overhaul of the power plant.
How often does the radiator on a Nissan Murano Z51 need to be replaced?
An original radiator with proper maintenance can last 10-15 years. However, due to road conditions and the quality of the antifreeze, it is recommended to inspect it every 5 years or when the first signs of corrosion appear.
Is it possible to drive with a crack in the radiator tank?
Absolutely not. Even a small crack will lead to rapid loss of coolant and overheating of the engine. Driving in this mode can lead to deformation of the cylinder head.
How to properly bleed the cooling system after replacing the radiator?
Fill the antifreeze to the maximum, close the lid, start the engine and let it run until the fan turns on. Open the lid (careful, it's hot!) and add liquid if necessary. Repeat the procedure 2-3 times.
Why does the engine get hot even though the radiator is new?
Causes could be an air lock, a malfunctioning thermostat, a faulty temperature sensor, or problems with the pump. A new radiator does not guarantee the absence of other faults in the system.
Can distilled water be used instead of antifreeze?
Only in emergency cases to get to the service. Distilled water does not have anti-corrosion additives and boils at 100°C, which is not enough for modern engines under load.